boid1 wants to get to boid2. with each step it takes towards boid2, the steps get larger, so it will eventually go past boid2, whereupon each step will get smaller until the steps become negative and boid1 reverses direction and moves towards boid2 again, it step it takes getting larger, and so forth. boid1 will continue spaffing
around boid2 forever. incidentaly, the 'shape' of its movement is a sin wave.